1. Field of the Invention
The invention relates to flame retardant compositions of compatibilized polyphenylene ether-polyamide resin blends containing at least one phosphoramide compound.
The invention also relates to the methods to prepare flame retardant compositions of compatibilized polyphenylene ether-polyamide resin blends and articles formed out of the compositions.
2. Brief Description of the Related Art
Poly(phenylene ether) resins (referred to hereafter as "PPE") are commercially attractive materials because of their unique combination of physical, chemical, and electrical properties. Furthermore, the combination of these resins with polyamide resins into compatibilized blends results in additional overall properties such as chemical resistance, high strength, and high flow. Examples of such compatibilized blends can be found in U.S. Pat. No. 4,315,086 (Ueno, et al); U.S. Pat. No. 4,659,760 (van der Meer); and U.S. Pat. No. 4,732,938 (Grant, et al). The properties of these blends can be further enhanced by the addition of various additives such as impact modifiers, light stabilizers, processing stabilizers, heat stabilizers, antioxidants and fillers.
The physical properties of PPE/polyamide blends make them attractive for a variety of end-use articles in the automotive market, especially for under hood and various exterior components. Additional applications in other markets have been somewhat limited by the lack of an effective flame retardant system for these blends. Some of the desirable applications, for example, electrical connectors require a flame rating in the Underwriters Laboratory UL-94 protocol of at least, V-0, V-1, or V-2. The same resins must also have outstanding ductility, flow, and surface appearance. Conventional phosphate ester flame retardant additives when utilized in PPE/polyamide blends have an inadequate balance of properties to widely penetrate many potential markets.
It is therefore apparent that a need continues to exist for flame retardant PPE/polyamide compositions that retain the other attractive physical properties.